Pressure activated valve for high flow rate and pressure venous access applications

ABSTRACT

A valve comprises a first housing including a first lumen extending therethrough and defining a first disk-facing surface and a second housing including a second lumen extending therethrough and defining a second disk-facing surface, the second housing being mated to the first housing so that the second disk-facing surface faces the first disk-facing surface in combination with a flexible disk gripped between gripping portions of the first and second disk-facing surfaces, the disk including a slit extending therethrough which, when acted upon by a fluid pressure of at least a predetermined threshold level opens to permit fluid flow between the first and second lumens and which, when acted upon by a fluid pressure less than the threshold level remains sealed preventing fluid flow between the first and second lumens and a relief well between opposing portions of the first and second housings radially outside the gripping portions, a width of the relief well exceeding a width of a radially outer portion of the flexible disk so that the radially outer portion of the disk is free to move therewithin.

BACKGROUND

Pressure activated safety valves may be incorporated into medical devices such as peripherally inserted central catheters (PICCs), ports, dialysis catheters and tunneled central catheters which provide long term access to the vascular system. Pressure activated safety valves generally include a slitted, flexible disk extending across a lumen. The flexible disk is generally constructed so that, when subjected to a threshold fluid pressure, edges of the slit separate from one another to permit flow through the lumen. When the pressure applied to the disk drops below the threshold level, the slit reseals to prevent leakage from or to the vascular access device. It would be desirable at times to employ within these vascular access devices fluid pressures in excess of the pressures to which these known flexible membranes have been traditionally exposed to with hand injections (e.g., when flushing an obstructed lumen, administering high-flow rate fluids, etc.).

SUMMARY OF THE INVENTION

The present invention is directed to a valve comprising a first housing including a first lumen extending therethrough and defining a first disk-facing surface and a second housing including a second lumen extending therethrough and defining a second disk-facing surface, the second housing being mated to the first housing so that the second disk-facing surface faces the first disk-facing surface in combination with a flexible disk gripped between gripping portions of the first and second disk-facing surfaces, the disk including a slit extending therethrough which, when acted upon by a fluid pressure of at least a predetermined threshold level opens to permit fluid flow between the first and second lumens and which, when acted upon by a fluid pressure less than the threshold level remains sealed preventing fluid flow between the first and second lumens.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a section view of a device, according to a first exemplary embodiment of the present invention;

FIG. 2 shows an enlarged view of the device of FIG. 1;

FIG. 3 shows a cross-sectional side view of capture area of a device, according to a second exemplary embodiment of the present invention;

FIG. 4 shows a perspective view of a portion of a second housing of the device of FIG. 3, according to a further embodiment;

FIG. 5 shows a perspective view of a portion of the second housing of the device of FIG. 3, according to an alternate embodiment;

FIG. 6 shows a cross-sectional a side view of a capture area of a device, according to a third embodiment of the present invention;

FIG. 7 shows a cross-sectional side view of a capture area of a device, according to a fourth embodiment of the present invention;

FIG. 8 shows a cross-sectional side view of a capture area of the device of FIG. 7, according to an alternative embodiment;

FIG. 9 shows a cross-sectional side view of a capture area of the device of FIG. 8, according to a further embodiment;

FIG. 10 shows a cross-sectional side view of a capture area of a device, according to a fifth embodiment of the present invention;

FIG. 11 shows a cross-sectional side view of a capture area of a device according to a sixth embodiment of the present invention;

FIG. 12 shows a cross-sectional side view of a capture area of a device according to a seventh embodiment of the present invention;

FIG. 13 shows a cross-sectional side view of a capture area of a device, according to an eighth embodiment of the present invention; and

FIG. 14 shows a cross-sectional side view of a capture area of a device, according to a ninth exemplary embodiment of the present invention.

DETAILED DESCRIPTION

The present invention may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The present invention relates to apparatus for controlling fluid flow through medical devices specifically for sealing devices which remain in place in the body to provide long term access to the vascular system. To improve the performance of pressure activated safety valves, embodiments of the present invention include features for fixing a disk and tuning the valve performance to withstand the increased pressures and flow rates associated with certain procedures.

As described in more detail below, exemplary embodiments of the present invention provide features for enhancing the performance of a pressure activated valve including a feature fixing a slitted, flexible disk in a desired position, a relief well to accommodate portions of the flexible disk moved out of the fixation area and a slit bias feature creating a bias aiding in tuning the performance of the valve (e.g., to select a threshold activation pressure).

As shown in FIGS. 1 and 2, a device 100 according to a first exemplary embodiment comprises a first housing 102 and a second housing 104 coupled to one another to hold a disk 106 therebetween. The device 100 may further comprise an additional capture component 108, such as an o-ring. As shown in FIG. 1, the first housing 102 may, for example, be located at a proximal end 122 of the device 100 while the second housing 104 may be located at a distal end 124 of the device 100. As shown in FIG. 2, the first housing 102 includes a lumen 110 extending therethrough and a disk-facing surface 112. The second housing 104 includes a lumen 114 extending therethrough and a disk-facing surface 116. It will be understood by those of skill in the art that the first housing 102 and the second housing 104 are brought together to hold a disk 106 therebetween such that a pressure activated slit in the disk is positioned between the lumens 110, 114 to control fluid communication therebetween. A circumference of the disk-facing surface 112 of the first housing 102 and the disk-facing surface 116 of the second housing may be substantially the same as a circumference of the disk 106 so that the first housing 102, the second housing 104 and the disk 106 are substantially aligned within the device 100.

The disk 106 may, if desired, operate as a bidirectional valve allowing fluid flow through the device 100 in either direction. Alternatively, the disk 106 may be structured or, one or both of the first and second housings 102,104, respectively, may include a structure preventing the disk 106 from deforming in one direction and opening to permit fluid flow through the valve in that direction. Thus, fluid flow would be permitted only in the other direction. Fluid may be being administered to the body via the device 100 when a fluid pressure applied to the proximal end 116 of the device 100 exceeds a threshold value at which the disk 106 deforms so that the slit of the disk 106 opens to permit fluid flow therethrough to the distal end 118 of the device 100. So long as the fluid pressure remains at least as great as the threshold level, the slit remains open and fluid passes through the disk 106 and the lumen 112 to the body. Fluid may be withdrawn from the body when a negative fluid pressure applied to the proximal end 116 exceeds the threshold level deforming the disk 106 and the slit thereof proximally to permit fluid flow from the distal end 118 of the device 100 to the proximal end 116 thereof. The fluid may be drawn from the body through the lumen 112 of the second housing 104. This fluid flow will be maintained so long as the fluid pressure remains at least the threshold value. As soon as the fluid pressure applied against the disk 106 in either direction drops below the threshold level, the disk 106 returns to the sealed configuration in which edges of the slit therethrough abut one another preventing fluid flow therethrough.

The disk 106 may be flexible such that the disk 106 may be held between the first housing 102 and the second housing 104 in a substantially planar configuration or in a deformed configuration, as shown in FIG. 2. The capture component 108, shown as an o-ring, may be housed between the first housing 102 and the second housing 104 such that when the disk 106 is held between the disk-facing surface 112 and the disk-facing surface 116, an outer edge 118 of the disk 106 is deformed so that an outer edge 118 extends away from a plane of a central portion 120 of the disk 106 into a relief well 120 formed around a circumference of the disk-facing surface 112 of the first housing 102. If it is desired to have a substantially neutral valve (i.e., a valve with substantially equal threshold pressure levels regardless of the direction of flow), the disk-facing surfaces 110 and 114, between which the disk 106 is fixed, may be formed substantially planar to hold the central portion 120 in place without bending it in one direction or the other. It will be understood by those of skill in the art, however, that other factors such as diameter, may also affect the tuning of the valve. In addition, either or both of those portions of the disk-facing surfaces 110, 114 contacting the disk 106 and forming fixation features of the first and second housings 102, 104, respectively, may be coated, textured, covered or overmolded with a thermoplastic elastomer or thermoset plastic such as silicone to enhance the coefficient of friction to aid in valve disk retention during high flow applications.

In another embodiment, the disk 106 may be non-planar. For example, rather than a planar surface as shown in FIG. 2, the disk 106 may have a concave or convex shape. It will be understood by those of skill in the art, however, that the disk 106 may take a variety of other non-planar shapes and forms so long as the disk 106 may be fixed between the first housing 102 and the second housing 104. It will also be understood by those of skill in the art that the disk 106 may include more than one slit which may be pressure activated. Additionally, either of or both of the first and second housings 102, 104, respectively, may include more than one lumen extending therethrough. With flow through each of these lumens controlled by separate slits or by one or more common slits extending across multiple lumens.

The following alternate embodiments, shown in FIGS. 3-14, are substantially the same as the device 100 described above, but may include alternate geometrical aspects forming the fixation feature, the relief well and the slit bias. For example, the first and second housings of the following embodiments align such that the lumen of the first housing is in fluid communication with the lumen of the second housing with a flexible disk secured therebetween so that a slit of the disk is positioned between the lumens to control fluid flow therebetween. Additionally, the figures show a capture area of the device in which the disk would be held such that the device is depicted via surfaces of a distal portion of the first housing and a proximal portion of the second housing.

As shown in FIG. 3, a device 200, according to another embodiment of the present invention comprises a first housing 202 and a second housing 204 for securing a disk (shown in broken lines) therebetween. The first housing 202 includes a lumen 206 extending therethrough and a surface 208, which faces a disk received in the space between the first and second housings 202, 204, respectively. The surface 208 may be substantially planar so that an entire area thereof contacts the disk. The second housing 204 includes a lumen 210 extending therethrough and a surface 212 facing the space in which the disk will be received. The surface 212 may further include at least one protrusion 214 forming a fixation feature pressing against the surface 208 a portion of the disk abutting thereagainst. The protrusion 214 may be formed as an annular ring encircling the lumen 210 radially within an outer circumference 216 of the second housing 204 with a circumference greater than an inner circumference of a wall 218 of the lumen 210. The protrusion 214 be formed by a continuous ring on the disk-facing surface 208 or, in an alternative embodiment, the protrusion 214 may be formed as a series of projections extending discontinuously around the lumen 210 (e.g., as a series of arcs extending along a curve around the lumen 210. For example, as shown in FIG. 4, the non-continuous ring shape may be formed by a series of castellated teeth of the disk-facing surface 208 of the second housing 204. In another embodiment, as shown in FIG. 5, the non-continuous protrusion 214 may be formed by a series of saw teeth. Such non-continuous geometries provide localized areas of grip on the disk. It will be understood by those of skill in the art that the protrusion 214 may be formed by any variety of geometrical shapes.

A space 220 radially outside the protrusion 214 (i.e., between the protrusion 214 and the outer circumference 216) forms a relief well into which a radially outer portion of the flexible disk will extend, substantially unsecured and enabled to flex accommodating the vibrations associated with high pressure fluid flow through the slit. Additionally, a space 222 radially within the protrusion 214 would allow a central portion of the disk, including the slitted portion, to flex toward the second housing 204, until the central portion of the disk contacts the surface 212. Thus, the device 200 will be able to withstand increased fluid pressures when fluid flows through the device in a positive direction (from the first to the second housing). It will be understood in the art, however, that the slit is not biased in any particular direction when there is no fluid flow through the device 200. Those skilled in the art will also understand that the designation of the first housing 202 as upstream (i.e., proximal) of the second housing 204 is exemplary only and may be reversed as may the location of the protrusion 214. That is, the second housing 204 may be formed as either the proximal or distal end of the valve of the device 200 and the protrusion 214 may be formed on either of the first and second housings 202, 204, respectively, in either the proximal or the distal of the two.

According to another embodiment of the present invention, as shown in FIG. 6, a device 300, comprises a first housing 302 and a second housing 304 for holding a flexible disk (shown in broken lines) therebetween. The device 300 is substantially similar to the device 200, described above with the first housing 302 including a lumen 306 extending therethrough and a surface 308 which faces a space in which a disk will be received. The surface 308 includes a protrusion 310, which may extend around the lumen 306 continuously or non-continuously as described above in regard to device 200. As described above in regard to the protrusion 214, the protrusion 310 has a circumference less than that of an outer circumference 312 of the first housing 302 but greater than an inner circumference 314 of the first housing 302 which forms the lumen 306. The second housing 304 includes a lumen 316 extending therethrough and a surface 318 which faces the space within which a disk will be received. The device 300 differs from the device 200, however, in that the surface 318 also includes a protrusion 320 which extends either continuously or discontinuously about the lumen 316. A circumference of the protrusion 318 is less than an outer circumference 322 of the second housing 304 but greater than an inner circumference 324 of the second housing 304 which forms the lumen 316. It will be understood by those of skill in the art that the protrusion 310 of the first housing 302 preferably substantially aligns with the protrusion 320 of the second housing 304 such that a disk held therebetween is gripped by the first and second housings 302, 304, respectively, with the protrusions 310 and 320 pressing portions of the disk inward toward one another. Thus, the protrusions 310, 320 form a fixation feature which holds the disk therebetween.

When the protrusions 310, 312 are aligned to hold the disk therebetween, a space 326 radially outside the protrusions 310, 320 forms a relief well allowing an outer portion of the disk to remain substantially unsecured therein to flex in either direction (i.e., toward the first housing 302 or toward the second housing 304) to accommodate the vibrations associated with high pressure fluid flow. A space 328 formed radially within the protrusions 310, 320 (i.e., between the protrusions 310, 320 and the lumens 306, 316) allows a central portion of the disk, including the slitted portion, to flex to accommodate high pressure fluid flow. In other words, the central portion of the disk may flex toward the first housing 302 until the disk contacts the disk-facing surface 308 and/or toward the second housing 304 until the disk contacts the disk-facing surface 318. Thus, it will be understood by those of skill in the art that the space 328 allows the disk to accommodate a high pressure fluid flow in either direction. However, it will also be understood by those of skill in the art, that when there is no fluid flow through the device 300, the disk need not be biased in any particular direction, either positive or negative.

As shown in FIGS. 7 and 8, a device 400, according to another embodiment of the present invention, comprises a first housing 402 and a second housing 404 for holding a flexible disk (shown in broken lines) therebetween. The first housing 402 includes a lumen 406 extending therethrough and a disk-facing surface 408 which includes a protrusion 410 extending from the surface 408. The protrusion 410 extends around the lumen 406 either continuously or non-continuously in the same manner described above radially within an outer circumference 412 of the first housing 402 and radially outside an inner circumference 414 of the first housing 402 which forms the lumen 406. An outer annular space between the outer circumference 412 and the protrusion 410 forms a relief well 428 while an annular space between the protrusion 410 and the inner circumference 414 forms a relief well 430. The protrusion 410 may also include a pointed tip 426, as shown in FIG. 7. The protrusion 410 may also be angled such that the pointed tip 426 is offset radially outward from a proximal end 432 at which the protrusion 410 meets the surface 408. It will be understood by those of skill in the art that the pointed tip 426 may provide an improved grip of the disk 106 over a flat-surfaces protrusion 410.

The second housing 404 includes a lumen 416 extending therethrough and forms a disk-facing surface 418 radially outside the lumen 416. The disk-facing surface 418 optionally includes an indentation 420 (or a series of indentations 420 if the protrusion 410 is non-continuous) corresponding to a shape of the protrusion 410 formed on the first housing 402 and angled similarly thereto. Thus, portions of a disk received between the first and second housings 402, 404, respectively, and pinched by the protrusion(s) 410 will be pushed into the indentation(s) 420, locking the disk in position with a slit therethrough aligned with the lumens 406 and 416 while the relief wells 428 and 430 allow for flexing of the disk and the accommodation of vibrations under high pressure fluid flow. Alternatively, a device 400 may include only a protrusion 410 without a corresponding indentation 420 and the same modification may be made to any of the devices 400, 400′ and 400″ described below.

Alternatively, a device 400′ as shown in FIG. 8 may include a protrusion 410′ and a corresponding indentation 420′ (or a series of non-continuous protrusions 410′ and indentations 420′) without the pointed tip of the device 400. Specifically, as shown in FIG. 8, the protrusion(s) 410′ and the indentation(s) may be substantially rectangular in cross-section to form similar radially outer and inner relief wells 428′ and 430′, respectively. In this case, a portion of a disk received between the first and second housings 402′, 404′, respectively, will be pushed by the protrusion(s) 410′ into the indentation(s) 420′, locking the disk in position with a slit therethrough aligned with the lumens 406′ and 416′ and so that the relief wells 428′ and 430′ allow for flexing of the disk and the accommodation of vibrations under high pressure fluid flow.

In a further embodiment of the device 400″ as shown in FIG. 9 is constructed in substantially the same manner as the device 400′ except that the first housing 402″ includes a second protrusion 434″ on a disk facing surface 408″ thereof which may be either continuous or non-continuous in the same manner described above for the protrusions of the previous embodiments while the second housing 404″ includes a second indentation 436″ on a disk-facing surface 418″ thereof which may correspond in shape and position to the second protrusion 434″. The device 400″ defines a radially outer relief well 428″ between the first protrusion 410 and an outer circumference 422″ of the first housing 402″ and a radially inner relief well 430″ between the second protrusion 434″ and the lumen 406″. It will be understood by those of skill in the art that the first and the second housings 402, 404, respectively may include any number of protrusions and indentations as desired to more secure retain a disk gripped therebetween.

As shown in FIG. 10, a device 500, according to another embodiment of the present invention, comprises first and second housings 502, 504, respectively include disk facing surfaces 508, 518 respectively for holding a flexible disk therebetween. The device 500 is substantially similar to the device 400, as described above except that, while the disk-facing surface 508 includes a protrusion 510 shaped and positioned substantially similarly to the projection 410 shown in FIG. 7, the disk-facing surface 518 of the second housing 504 includes no corresponding indentation and, in this case, is substantially planar such that, when a flexible disk is positioned between the first and second portions 502, 504, respectively, with a slit thereof aligned with the lumens 506 and 516, portions of the disk contacting the protrusion(s) 510 are pinched against the flat surface 518 locking the disk in position while radially outer and inner relief wells 522, 524, respectively, allow for flexing of the disk and the accommodation of vibrations under high pressure fluid flow.

According to another exemplary embodiment shown in FIG. 11, a device 600 comprises a first housing 602 and a second housing 604 for holding a flexible disk (shown in broken lines) therebetween. The first housing 602 includes a lumen 606 extending therethrough and a disk-facing surface 608. The disk-facing surface 608 includes an inner portion 610 immediately surrounding the lumen 606 and an outer portion 612 extending radially from the inner portion 610 at a distal end of the lumen 606. The outer portion 612 may be substantially planar and oriented in any desired relationship to an axis of the lumen 606 (e.g., substantially perpendicular thereto). The inner portion 610 is angled such that a proximal opening 606′ of the lumen 606 is smaller than a distal opening 606″ thereof. That is, in this embodiment, the lumen 606 is substantially conical flaring outward distally.

The second housing 604 includes a lumen 614 extending therethrough to a proximal disk-facing surface 616. The lumen 614 may for example be substantially cylindrical and approximately equal in diameter to the proximal opening 606′ of the lumen 606. The disk-facing surface 616 includes a radially inner portion 618 separated from a radially outer portion 620 by a protrusion 622 which may be formed as described in regard to any of the above embodiments. The inner portion 618 is angled so that, when the first and second housings 602, 604, respectively, are mated to one another with a slitted, flexible disk gripped therebetween, it is substantially parallel to the inner portion 610 of the first housing 602. Furthermore, as would be understood by those skilled in the art, although distal opening 606″ is wider than the proximal opening 614′, the flexible disk (shown in broken lines) will preferably have a slit which is no wider than the opening 614′ and which, when gripped between the first and second housings 602, 604, respectively, will be entirely radially within the opening 614′ so that fluids will pass from the lumen 606 to the lumen 614 without leaking along the inner portion 618.

As in the above-described embodiments, the protrusion 622 extends continuously or non-continuously around the lumen 614 separated therefrom by the inner portion 618 and separated from an outer circumference 624 of the second housing 604 by an annular space forming a relief well 626. It will be understood in the art that when the first and the second housings 602, 604, respectively, are mated together to secure a flexible disk therebetween, the flexible disk will bend to accommodate the angled inner portions 610, 618 with a portion of the flexible disk secured between the outer portions 612, 620 fixed to the outer portion 612 of the disk-facing surface 608 by the protrusion 622. Additionally, it will be understood by those of skill in the art that in order to accommodate the angled inner portions 610, 618 a central portion of the disk, including the slitted portion, bends in a proximal direction.

As shown in FIG. 12, a device 700 according to another embodiment of the invention comprises a first housing 702 and a second housing 704 for holding a flexible disk (shown in broken lines) therebetween. The first housing 702 includes a lumen 706 extending therethrough to a distal opening 706′ surrounded by a disk-facing surface 708. An inner portion 710 of he disk-facing surface 708 is substantially conical, angling proximally away from the opening 706′ to meet a substantially planar outer portion 712 extending radially outward therefrom. The second housing 704 includes a substantially conical lumen 714 extending therethrough from a proximal opening 714′ to a smaller distal opening 714″. The proximal opening 714′ is surrounded by a disk-facing surface 716 separated from the opening 714′ by a protrusion 722. The inner portion 718 comprises a wall immediately surrounding the lumen 714 and is shaped, for example, to correspond to the shape of the inner portion 710 of the first housing 702. That is, in this embodiment, the inner portion 718 is angled such that the lumen 714 is recessed relative to the outer portion 720. As in the previously described embodiments, the protrusion 722 may extend continuously or non-continuously around the opening 714′ within an outer circumference 724 of the second housing 704 to define a relief well 726 within which will be received a radially outer portion of a slitted, flexible disk to be gripped between the first and second housings 702, 704, respectively. As described above, the disk will be pinched between the projection 722 and the outer portion 712 and between the inner portions 710 and 718 leaving the radially outer portion of the disk free to vibrate when exposed to high flow rates.

As will be understood by those of skill in the art, the flexible disk will bend to accommodate the angled inner portions 710, 718 of the disk facing surfaces 708, 716 creating a positive slit bias reducing the pressure required for flow proximal to distal as compared to that required for flow from the distal to the proximal.

As shown in FIG. 13, a device 800 according to another embodiment of the invention comprises a first housing 802 and a second housing 804 for holding a flexible disk (shown in broken lines) therebetween. The first housing 802 includes a lumen 806 extending therethrough and a disk-facing surface 808 including a recessed portion 810 extending around an outer-most perimeter of the disk-facing surface 808. That is, a portion of the first housing 802 radially outside the disk-facing surface 808 is recessed away from the second housing relative to the disk-facing surface 808. The second housing 804 includes a lumen 812 extending therethrough and a disk-facing surface 814 which includes a non-continuous or continuous protrusion 816 as described above extending around an outer-most perimeter of the disk-facing surface 814. A radially inner surface of the protrusion 816 is radially further from the lumens 806, 812 than the outer perimeter of the disk-facing surface 808 so that an annular gap extends there between when the first housing 802 is coupled to the second housing 804 with a flexible disk gripped therebetween. It will be understood by those of skill in the art that although the protrusion 816 is described as formed on the disk-facing surface 814 of the second housing 804, an o-ring may be included in the device 800 as an alternative to the protrusion 816. In this alternative embodiment, the o-ring may be placed between the first and the second housings 802, 804 when the disk is being fixed therebetween in substantially the same position described for the protrusion 816.

A circumference of the disk-contacting portion 818 of the disk-facing surface 808 may be smaller than a circumference of the protrusion 816 on the disk-facing surface 814 such that when the first and second housing 802, 804 are mated, a relief well 822 is formed by an annular space between an inner surface 824 of the protrusion 816 and an outer surface 826 of the disk-contacting portion 818. The disk may be fixed between the first and the second housings 802, 804, respectively, such that the disk-contacting portion 818 secures the disk to a disk-contacting portion 820 of the disk-facing surface 814 radially within the protrusion 816. It will be understood by those of skill in the art that the disk may be positioned therebetween such that the disk is substantially planar or, in the alternative, such that outer edges of the disk are deformed, as shown in FIG. 13, by the protrusions 816. Thus, an unsecured radially outer portion of the disk may flex within the relief well 822 to accommodate high pressure fluid flow therethrough. As the remaining portion of the disk is firmly secured between the disk-contacting portion 818 and the disk-contacting portion 820, it will be understood by those of skill in the art that the a neutral slit bias exists, meaning that, in this embodiment, the device 800 opens to permit flow from proximal to distal at substantially the same threshold pressure as it opens to permit flow from distal to proximal.

As shown in FIG. 14, a device 900 according to another embodiment of the invention comprises a first housing 902 and a second housing 904 for securing a flexible disk (shown in broken lines) therebetween. The device 900 is substantially similar to the device 800 described above except that the first housing 902 includes a protrusion 910 extending continuously or non-continuously around an outer-most perimeter of a disk-facing surface 908 as described above while the second housing 904 includes a recessed portion 914 extending around an outer-most perimeter of a disk-facing surface 912, radially outside a disk-contacting portion 920 of the disk-facing surface 914. Similarly to the device 800, the first housing 902 includes a lumen 906 extending therethrough while the second housing 904 includes a lumen 912 extending therethrough. A circumference of the disk-contacting portion 920 of the disk-facing surface 914 is smaller than a circumference of the protrusion 910 on the disk-facing surface 908 such that, when the first and second housing 902, 904, respectively, are mated to one another, a relief well 922 is formed by an annular space between an inner surface 924 of the protrusion 910 and an outer surface 926 of the disk-contacting portion 920. Thus when a disk is fixed between the first and the second housings 902, 904, respectively, with the disk-contacting portion 920 securing the disk to a disk-contacting portion 918, an outer edge of the disk is free to flex within the relief well 922 when a high pressure fluid flow passes therethrough. Similarly, it will be understood by those of skill in the art that although the protrusion 910 is described as formed on the first housing 902, an o-ring may be included in the device 900 in place of the protrusion 910 between the first and the second housings 902, 904, respectively, in the same position occupied by the protrusion 910.

It will be apparent to those skilled in the art that various modifications and variations can be made in the structure and the methodology of the present invention, without departing from the spirit or scope of the invention. For example, in any of the embodiments any of the features mentioned for a first housing may be moved to a second housing and vice versa. In addition, features mentioned with respect to controlling flow in the distal to proximal direction may be reversed to obtain the same effect in proximal to distal flow and vice versa. Thus, it is intended that the present invention cover any modifications that come within the scope of the appended claims and their equivalents. 

1. A valve comprising: a first housing including a first lumen extending therethrough and defining a first disk-facing surface; a second housing including a second lumen extending therethrough and defining a second disk-facing surface, the second housing being coupled to the first housing so that the second disk-facing surface faces the first disk-facing surface; a flexible disk gripped between gripping portions of the first and second disk-facing surfaces, the disk including a slit extending therethrough which, when acted upon by a fluid pressure of at least a predetermined threshold level opens to permit fluid flow between the first and second lumens and which, when acted upon by a fluid pressure less than the threshold level, prevents fluid flow between the first and second lumens; and a relief well between opposing portions of the first and second housings radially outside the gripping portions, a width of the relief well exceeding a width of a radially outer portion of the flexible disk so that the radially outer portion of the disk is free to move therewithin, the relief well including a first protrusion that deforms the radially outer portion of the flexible disk so that it extends away from a plane defined by a central portion of the disk.
 2. The valve of claim 1, wherein one of the first and second disk-facing surfaces includes the first protrusion extending therefrom toward the other of the first and second disk-facing surfaces, the first protrusion extending around the first and second lumens between the first and second lumens and the relief well.
 3. The valve of claim 2, wherein the first protrusion is formed between an outer circumference and an opening of the lumen of one of the first and second disk-facing surfaces.
 4. The valve of claim 2, wherein the first protrusion extends substantially continuously around a circumference thereof.
 5. The valve of claim 2, wherein the other of the first and second disk-facing surfaces includes a second protrusion extending therefrom toward the one of the first and second disk-facing surfaces radially outside the first protrusion so that the relief well is formed between the first and second protrusions.
 6. The valve of claim 2, wherein the first protrusion is formed as an o-ring received between the first and second housings.
 7. The valve of claim 1, wherein the relief well is formed by a recessed portion formed in one of the first and second housings and extending around the corresponding one of the first and second lumens radially outside the corresponding gripping portion.
 8. The valve of claim 1, where the flexible disk includes a plurality of slits extending therethrough.
 9. The valve of claim 1, wherein the first housing includes a third lumen extending therethrough.
 10. The valve of claim 9, the second housing including a fourth lumen extending therethrough in alignment with the third lumen of the first housing.
 11. A valve comprising: a first housing including a first lumen extending therethrough and defining a first disk-facing surface; a second housing including a second lumen extending therethrough and defining a second disk-facing surface, the second housing being coupled to the first housing so that the second disk-facing surface faces the first disk-facing surface; a capture component held between the first and the second housings; a flexible disk gripped between said first and second disk-facing surfaces and said capture component, the disk including a slit extending therethrough which, when acted upon by a fluid pressure of at least a predetermined threshold level, opens to permit fluid flow between the first and second lumens and which, when acted upon by a fluid pressure less than the threshold level, prevents fluid flow between the first and second lumens; and a relief well between opposing portions of the first and second housings radially outside of the disk-facing surfaces, wherein a width of the relief well exceeds a width of a radially outer portion of the flexible disk so that the radially outer portion of the disk is free to expand therewithin wherein the first disk facing surface includes a first portion and the capture component includes a second portion, and each of said first and second portions deform said radially outer portion so that it extends away from a plane defined by a central portion of the disk. 